1. Field of the Invention
The present invention relates to a process for producing a vinyl chloride copolymer which has good moldability and can be made into polyvinyl chloride moldings having a good matte finish surface and superior in permanent compression set resistance, creep resistance, heat resistance, and electrical properties.
2. Description of the Prior Art
The thermoplastic elastomeric composition composed mainly of vinyl chloride resin has an advantage in moldability over other compositions such as rubber. That is, it can be molded by extrusion or injection. The resulting molded products, however, have low permanent compression set resistance and creep resistance and also have a surface which is not easily matte-finished.
A conventional means to overcome this disadvantage is to increase the degree of polymerization of vinyl chloride resin or to add a cross-linkable monomer to vinyl chloride at the time of polymerization, thereby increasing the apparent degree of polymerization of vinyl chloride resin. However, it has a shortcoming that the vinyl chloride resin having an increased degree of polymerization is extremely poor in moldability and needs a special processing machine and technology in order for it to exhibit the desired physical properties.